Vernier condenser



June 7, 1927,.

1,631,738 F.KOCH

VERNIER CONDENSER Filed Avril 28. 1924 2 Sheds-Shag. l

June 7, 1927. 3 ,738

F. KOCH VERNIER CONDENSER Filed Avril 28. 1924 2 Sheets-Sheet 2 A PTOR/VIY.

Patented June 7, 1927.

UNITED STATES FREDERICK KOCH, or Newman, NEW J RSEY, AssIGNoR TO U. s.

A CORPORATIQNQ VERNIER PATENT OFFICE.

TOOL COMPANY, INC.,

CONDENSER.

Application filed April 28, 1924. Serial No. 709,397. 7

My invention relates to variable con-' densers such as now generally used-in radiotelephony and telegraphy, and. it has for its objectthe provision of an improved form of reduction gear train for changing the quick knob rotation into a materially slower rotor rotation, whereby the requisite capacity adjustments may be effected without the use of supplemental rotor and stator plates.

Another object is to provide an improved form of spacing washer which will accu rately space the several plates of the condenser, and also aid materially in the rapid assembly of the parts in the process of manufacture.

Other minor objects and improvements will be disclosed in the following detailed description in connection with the accompanying drawings, wherein,

Fig.1 is a plan view of the complete condenser.

F ig. 2 is a section on line II-II of F ig. 1, showing the bottom frame plate and gear train in plan.

turning knob and inde'x plate orfdial' removed.

Fig. 4 is a section'throughthe central shafts and through the gear train.

Fig. 5 is a section of the rotor shaft, showing the form of the rotor plates and the spacing washers for separating the same.

Fig. 6 illustrates the method of forming the washers in a helical coil upon a mandrel, and thereafter serving them by a'single cut in a line parallel with the axis of the'helix.

Fig. 7 is a plan of a washer upon the mandrel preparatory to upsetting the same to form the fiattedside.

Fig. 8 is an edge View of a washer.

Fig. 9 is a section on. line IX- IX of Fi Fig. 10 is a section on line XX of Fig. 2.

Fig. 11 is a plan of one of the rotor plates.

Figure 12 is a. fragmentary view similar to Figure 2 but showing a modified form of star spring and support.

Figure 13 is a fragmentary sectional view similar to Figure 9 indicating a glass panel.

Similar reference numerals refer to like parts throughout the specification and draw lng; I

The condenser consists of the frame for supporting the stator plates and for pivotally supporting the rotorf The frame is made up of the top platel, the'bottom plate 2, and the posts or bolts 3, 4, 5. Upon these bolts are mounted-the "several'stator plates -6, spaced apart by the'spacingj-was'hers 7,

and from the plates rand? hy'the hexagon spacing washers 8, whi'chare ofa thickness of at least three times th'atfof. thdwashers 7. "."The-bolts 3, 4', 5 am insulated from the two plates 1 and 2, by means of the laminated mica insulation and the mica washers 10, 11, placed shown under'thefl bolt head and between"the"wa'shers 8' and the respective: plates l 'and 2.1""A' similar method in insulation ,i s'"em-ployed for the threaded end of the bolts and with their" holding hints as shown iii Fig.' 1O.- The bolt. holes treeonsid'rabiy largeftliairthe y =bq1ts, and"'are filled' with thttmflumit Fig. 3' is a plan of the top plate with the 1 washers, and 1 thelarger disltsfof 'inic'afefi'ec tually protect the nuts. from "contact with. themetal'of the"-'frame'pl'ate Theroto r consists of the-central tubular shaft"13,upon {which thsemifeii cular late's 14*afe'secured. The"s hi' iftl 3i"isma e of i any formofrod which is polygonal in cross- "section, that shown being hexagonal. Such a rod is turned down at eaeli end to cyli n' 'drical form so as to leave the original poly onal'shap e for a" distai ce eqifalfto the com 'plete for combined thicklie sis; all or the plates with their spacing'fwashers 15'when. assembled, so that the clamping "collar 16 at the. upper or outer end serves'as "an abutjment against which the first plate may rest; While the gang'of plates and washers are '90 held firmly clamped by the nut" l7 screwed on the threaded part of the other'end of the shaft. The rotor plates '14 andthe shaft 13 are mounted between the end plates 1, 2, so as to interleave said plates between 9 the stator plates 6. It will be noted that'f the holes in the rotor plates ar'e of the same shape a-s the cross-section of' th'e shaft, so"

..the stator.

as to form a fairly close fit thereon. This enables me to assemble the rotor plates very quickly and in proper position without the use of the usual assembling gigs, and when the nut 17 is screwed up all of the plates are accurately aligned. This simple construction reduces the time OCQLlPlQtliIlflSSOIQ- bling the rotorparts from one'third to one half, resulting in a materially increased output per each operative, and a correspondingly:reducedcost of manufacture.

The spacing ,washers hithertouniversally used have been the usual punched washers, and in assembling the stator and'aot or, it has been necessary to line .npdhe setsoi washers to be used upon posts, because ofthe 'arying thicknessolf the ,individual washers; otherwise, it would ,begfoundthat the aggregate thickness of one gang of washers would vary from another, or that a slight burr upon one washer would-throw .an entire gang out of true with another gang. Much time has been-spent in assem: bling the plates to get them allaccurately spaced, andso thatlthe plates of the rotor will properly..interlea\{e with the plates of TOVOVBYCOIDC this diflieulty, and secure-accurate parallelism of the plates of both :rotor and stator, I makethe spacing washers? and 15 of wire of suitable,gage. The .wiretisfirstpassed between heavy rollers to providefiattened surfacesupon 0p; posite sides; it is then wound upon a man drel, as 18, in tlie .-saine manner asisused to.forn1 helical springs, but-withthe vf :lattened facesof, the. wire in contact, A'l0ngi tudinal cutis'thenmade parallehto the; axis bled. rotoror stator, for as the n ut s il2 or the nnt .17 areiscrewed np .the ..otherwise warped washeris compressed flat. and serves to .hold the adjacent parts firmly. in place,

and themselves against shifting. in. substan tially the same way as with the well-known lockwwasher. .Another advantage from-the use of the spacing washers Y as shown resides inthe economy of material;.there is practi; callyano waste, since the wire irom .which' the washersare. made is all used, whereas, in the. cut orpunched washer,-m ore than halflofthe material-goes into scrap. This material economyamounts to a large sum when the enormous number of condensers made; and vused isconsidered.

Another improvement of the condenser residesin the formof so-called pig-tail connection,orleadfor the rotor. Uponthe rotorshaft 13, just outside of the plate 1, isametallic spool 20,-with fiber or bakelite flanges 21. .Upon this spool is thestrip of p I I even withthe weake of the mandrel as at 19, thus -seyering thd; of-lneasun mgnt. rg

coil intogas many separate, washers as, there. were, convolutions .in -tl1e enti1e..coil. The. individual. .w-ashers V 15.. have their severed -endsotfset,.as. shown i1 1 Fig..-8; .these offset ends are a'distinct advantagein the. assem;

covered coil conductor 22, with its inner end firmly secured to the metal spool and its outer end fastened to the double ended clip 23, which is secured to the plate 1 by the screw 24. The lead wire 25 is fastened to the other end of the clip, as shown. The turning ,of tlryshaft l3 coils and .uncoils the spiral springjike tolnniector22, without in any way atl'ecting the positive metallic connection between the outside lead wire a nd tlie rotoFph-ttes: "-'I his' is'a-very material -advantage' in-devices of this kind, for the reason the contact connections hitherto 'used have rendered the condensers subject to im'fo iespen ca pacity losses, and when it s is considered that the currents used are very weak, any capacity loss,{however-slight,.becomes-a serionsmatter when absolute-acew 'racy.js;thecveryz thingito;be=attai31ed.- In.order to still giurther reduce capacity losses in .thecondenser I efliect .-a moreintiniatemetallic; connectiombetween: the several rotorplates 14gandttheaspaeingwashers I W t -th haiel t'by ippina he'fl r I rotor-in a very; ,thimbath; of; molten tin,. 50 9" as to,gi'v.e, the rotora completemetallic coating. .The same; resultmay be accomplished f y imn ii ng th remain a n e n l I P a n ba s Q fa a y m li .P' 1; ing, bath, ,and ,qoating. the. entire'isurfaeewifi the rotor with a continuous layer-,gf lmetal. i ssee metr ease a es m nim ta a eth hli-t-ia-Mtmtia dto. det rm n i lstwh eit qys:bmej amtb tz yg h i on:. proveinents set forttmldaive,l eemable ,to; we elat haws-t at e pt e bms li e t 'e b e s current susceptible;

d. a ah -sh wl at ie tiae an J cki qtithqlrabel, ihg ig ial' .27, I l secured' 'the'retol "The 'dial -is'in dex ed lasat fqrnr ht ycwithtt e. snal fi e p in er 11 m the was that bea e g fli is luii tfimsi yfe iu's 'm s ZIn practice,lhpwkvegithesd adjustments; are reqiiirdjqlbe}iieny liiie, muehmore minute i be ordinal? I efiectedlby. simple 1 ,turninfgjof 'theiditmhthelusfial 'knob. 'ifln 1.

'pasafia ti aamtadiasme sl a s ia $3. ,6. awe-mi m l t a ears, gate ays jsingllfturngbf ,t knpb will'r duei;bafi ,i return-5r fthe dlal'a'nd' rotor? hiisr a cenr 1120 .tral apertured ,boss ZQ thrQughHWhiQh' .the {rotor shaft isiinserted' secured by the set screw 30: It will be'noted'thatthe shaft 13,does, noQeggtendthroughihe end plate .2, but; only short ilistance beyond' the cla npi'ngjnut, 1-7,, Through th'ej'sha'ft13 eiten ds them-nitric ,driving shaft. 31 with its inner end journaledjfinthe plate,2,vand

its ,onter,.,end extending jheyond the .outer end ofshaft13,1md1having.securedthereto the turning knob;32.=a; :-Upon .theaishaftr. 31, justinside the plate-2, isus'eculred the small pinion 33, vandaiponlthelstubszshaft 34 a large-gear wheel iis.mountedtov ma rotate in-.meshiiwithtthefpinion 33: Upon the stub shaft 34- is theisinall pinion36. held: in frictional engagement .with the gear wheel 35 by the star spring 37. Upon the end of the shaft 13 is the rigidly secured large gear wheel 38, in mesh with the pinion 36. By the construction described it will be seen that the rotation of the shaft 31 by means of the turning knob 32, will be communicated to the shaft 13, through the pinion 33, the gear wheel 35, pinion 36 and gear wheel 38, but at a ratio depending upon the relative diameters of the pinions and gear wheels. The stub shaft 34 is secured to the plate 2 by the nut 39 which is screwed upon the protruding end of the shaft. The shaft provided with an eccentric bearing for the wheel 35 and pinion 36, so that by loosening the nut 39, the shaft may be turned to properly adjust the wheel and pinion into proper mesh with the pinion 33 and wheel 38, in order to take up all of hack-lash, and avoid any lost motion in the gear train. The end play of the shaft 31 is prevented by the rigidly secured pinion upon the inside of the plate 2 and collar 40 upon the outside of said plate.

The same results are accomplished by the structure illustrated in Fig. 12, wherein the shaft 13, the shaft 31, the pinion 33 and gear wheel 38 are the same as illustrated in Fig. 2. The gear 35, pinion 36, with the star spring 37 and stub shaft 34, are carried upon the free end of the arm 49, the latter being supported upon a post 34' which is secured in the end plate 2. The coil spring is wound around the post 34. with one of its ends bearing against a stud 51, inserted in the end plate 2, and and its other end 50 bearing against the outside of the swinging arm 49; the purpose being to press the teeth of the pinion 36 into close engagement with the gear 38, and the gear 35 into similar engagement with the pinion 33, to overcome any backlash. The safety pin 52 is inserted into the plate 2, as shown, to limit swing of the arm 49 so that the pinion 36 and gear 35 cannot be swung outside of the edge of the plate 2. The purpose of the structure is, as above set forth, to maintain a close engagement of the said gears and pinions when turning of the knob 32 to make the requisite adjustments.

In the use of variable condensers of the type above described it has been the practice to nialre the frame plates 1 and 2 of some insulating composition as vulcanized rubber. fiber, baltelite, and condensite or the like. Careful tests of instruments provided with such end plates show that there is a capacity existing between the metallic plates l1:anda2,-'-and-plates-6and14if such end plates arezin any .way connected with any oft-the; outside; circuits of the condenser a material-loss of cu-rrent-; is shown, particularly dzbtherotor is turned to produce mini mum:capacitynneasurements that the loss be reduced to as low a point as is possible. For that reason the end plates 1 and 2 are shown as removed to a distance from the stator plates.

I have made the further discovery that it is possible to further insulate the end plates when such plates are made of such insulating material as vulcanized rubber, fiber, bakelite, or other recognized insulating material. This is done 11' the manner shown in Fig. 13, wherein all of the parts are the same as those shown in Fi 9 with the exception of metal plate 1. 11 place of which I use any of the above insulating materials as may be desired. The post 3 the plates 6 spacing washers 7 and 8 are the same as is also the mica washers 9, 10, and 11. The same form of insulation should be applied to the post 3 as shown in Fig. 10 by the substituting of insulating material for the plate When thus contracted the most accurate tests with the most delicate testing instruments available have failed to show any capacity existing between the plates 6 or 14 and end plates 1' and 2. This in effect amounts to insulating an insulating material.

The plate 1 is provided with the three posts 41, 42, and 43, by which the condenser is secured to the panel 26. It is also provided with the two stop posts 44, 45, which are engaged by the stop pin 46, projecting from the side of the spacmg collar 47 upon the shaft 13. In this manner, the rotor is limited in its rotation to a half rotation, that being sufiicient to completely interleave its plates with those of the stator, or to swing the rotor plates completely free of interleaving relation with said stator plates. If upon turning the knob 32 until the stop pin 46 engages either one of the stop posts, a further turn is attempted, no harm can be done to the instrument, for the frictional engagement of the pinion 36 and wheel 35 will slip, and thus all liability to injury is obviated.

From the foregoing description, it will be seen that the results obtained from the improved construction, while apparently insignificant when taken separately, yet in the aggregate, indicate that the principal, if not practically all of the sources of capacity losses have been taken care of and removed; at the same time, the improvements are such as to materially reduce manufacturing costs to a minimum.

Minor changes coming within the scope of the appended claims are contemplated.

I claim said shaft, and spacing washers surround- In a variable condenser,.the combination ing said shaft between said plates, said of a supporting frame, a rotor shaft shers each beingxiormed of a single con- 10 mounted therein, said shaft having a-polygvolutio n"of flattened wire and having its 5 onnl cross-section for a portion of its length, off-set ends inwardly-bent to conform to a a plurality of rotor plates having apertures face of said polygonal shaft. therethrough to fit the polygonal section of FREDERICK KOCH. 

